Chemistry Reference
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X
N
r k
1 a k .1 C r k / ;
g.0/ D ˇ S
k
D
1
and if we assume that
X
N
r k
1 a k .1 C r k / 1;
(4.46)
kD1
then g.0/ ˇ S , so there is a root between each pair of consecutive poles and there
is either a positive and a negative root, or zero and a positive or negative root, or
zero with multiplicity two before the smallest pole. So all roots are real and they are
between 1 and +1 if g. 1/<ˇ S
C 1.
Example 4.10. As a special case consider linear price and cost functions i.e., p D
f.Q/ D A BQ and C k .x k / D d k C c k x k respectively. Then from Example 1.1
we know that r k
D 1=2 for all k. In this case
a k C ˇ S
2
.a k C ˇ S /.1 C r k / D
<1;
if a k C ˇ S is below 2, which always holds if both a k and ˇ S are less than or equal
to 1 and at least one of them is below one. Condition (4.46) also has the special
form
X
N
1
2 a k 1;
k
D
1
which clearly holds if N 2 and 0 a k
1. In this special case
N
N
X
X
r k . a k S /
2 a k .1 C r k / D
a k C S
4 a k
g. 1/ D
;
k
D
1
k
D
1
so the equilibrium is locally asymptotically stable if
X
N
a k C S
4 a k
S
C 1:
kD1
Notice that this relation can be rewritten as
N
4 a k 1 ! <1
X
X
N
2
a k
4 a k :
ˇ S
kD1
kD1
If the firms select identical adjustment schemes, then a 1
D D a N
D a,sothis
relation simplifies to
ˇ S 2N
4 a 1 <1
Na
4 a ;
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